This version of the AFT HMI Baseline was created by assimilating hourly HMI.M_720s magnetograms (http://jsoc.stanford.edu/HMI/Magnetograms.html) beginning May 1rst 2010 through May 1rst 2021. AFT maps for this series are output at a cadence of 8 hours per day (at 0,8, and 16 hours). The data for each year are saved into a separate zip file. The output data are provided as both as data file (.dat) and the accompaning image file (.gif). IDL code to read in the AFT maps in the .dat file format:

      a1=assoc(1,fltarr(1024,512))
      dateString=Year + Month + Day
      mapString=dateString + '.00'
      mapFile=Path + Year + '\' + mapString + '.dat'
      openr,1,mapFile
      bmap=a1(0)
      close,1

Each file is a 1024x512 array in longitude and latitude. 
The longitude of each pixel is given by
      longitude=fltarr(1024)
        for i = 0, 1023 do longitude(i)=(i+0.5)*360./1024.
The latitude values of each pixel is given by
      latitude=fltarr(512)
      for j=0,511 do latitude(j)=-90. + (j+0.5)*180./512.

I will be updating the file format to the .fits files, including relevant keywords. In the meantime, if you have any questions or if you need a specialized AFT series (e.g., different cadence) please feel free to reach out to me. 